Java 学生对象数组
下面是我的教授给我的硬件:Java 学生对象数组,java,arrays,Java,Arrays,下面是我的教授给我的硬件: 定义扩展Person的类学生。它添加了属性 Int Test1、test2、test3 双倍平均 弦级 它有computeaverage()和calculategrade()方法。分数基于平均值,高于90 A、80至90 A B、70至80 A C等。所有其他属性都有一个集合和一个get 编写一个使用大小为20的student类型数组的应用程序。该程序提示用户课堂上有多少学生,然后允许用户输入学生和他们的考试成绩,然后计算他们的成绩并打印出学生和成绩列表 话虽如此 周
public class Person {
/**
* @param args the command line arguments
*/
public static void main(String[] args)
{
Scanner kbd = new Scanner(System.in);
Student newStudent = new Student();
int size;
System.out.println("Enter the amount of students:");
size = kbd.nextInt();
Student[] myStudent = new Student[size];
String firstName;
String lastName;
int test1, test2, test3;
Student s;
for (int i=0; i < size; i++)
{
System.out.println("Enter first name of student: " + i);
firstName = kbd.next();
System.out.println("Enter last name if student: " +i);
lastName = kbd.next();
System.out.println("Please Enter first test score: ");
// JOptionPane.showInputDialog("Please enter first test score:");
test1= kbd.nextInt();
System.out.println("Please enter second test score");
// JOptionPane.showInputDialog("Please enter second test score:");
test2= kbd.nextInt();
System.out.println("Please enter third test score");
// JOptionPane.showInputDialog("Please enter third test score:");
test3=kbd.nextInt();
// s = new Student (test1, test2, test3, firstName, lastName);
myStudent[i].setTest1(test1);
myStudent[i].setTest2(test2);
myStudent[i].setTest3(test3);
myStudent[i].setfName(fName);
myStudent[i].setlName(lname);
}
for (int i = 0; i < size; i++)
{
System.out.println(myStudent[i].getGrade());
}
}
}
public class Student extends Person{
int test1, test2, test3;
double average;
String grade, firstName, lastName;
public Student()
{
test1 = 0;
test2 = 0;
test3 = 0;
average = 0;
}
public Student(int test1, int test2, int test3, String firstName, String lastName)
{
this.test1 = test1;
this.test2 = test2;
this.test3 = test3;
this.setfirstName = firstName;
}
public double computeAverage()
{
average = (test1 + test2 + test3)/3;
return average;
}
public String calculateGrade()
{
average = computeAverage();
if (average < 60){
grade = "F";}
else if (average < 70){
grade = "D";}
else if (average < 80){
grade = "C";}
else if (average < 90){
grade = "B";}
else {
grade = "A";
}
return grade;
}
public int getTest1() {
return test1;
}
public void setTest1(int test1) {
this.test1 = test1;
}
public int getTest2() {
return test2;
}
public void setTest2(int test2) {
this.test2 = test2;
}
public int getTest3() {
return test3;
}
public void setTest3(int test3) {
this.test3 = test3;
}
public double getAverage() {
return average;
}
public void setAverage(double average) {
this.average = average;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
}
公共类人物{
/**
*@param指定命令行参数
*/
公共静态void main(字符串[]args)
{
扫描仪kbd=新扫描仪(System.in);
学生新闻学生=新学生();
整数大小;
System.out.println(“输入学生人数:”);
大小=kbd.nextInt();
学生[]myStudent=新学生[人数];
字符串名;
字符串lastName;
int test1、test2、test3;
学生证;
对于(int i=0;i
通常,您希望尽可能多地封装字段。这意味着要做这些
int test1, test2, test3;
double average;
String grade, firstName, lastName;
私事。然后需要getter和setter从类外访问它们。这是件好事。但是,在类内部,您可以使用它们,而无需使用getter或setter
这回答了你的问题吗?我不知道第37行是什么,因为您没有提供编号。:)
编辑:如果您不知道,构造函数可能会被重载。您有两个不同的构造函数,一个带参数,一个不带参数。您可以选择要使用哪一个来构造类,您可能希望使用第二个
如果您需要两个构造函数,一个是完整的,另一个是使用默认值的,那么您可能需要考虑从第一个构造函数内部引用第二个构造函数,以避免代码重复。像这样:
public Student() {
this(0,0,0);
}
public Student(int test1, int test2, int test3, String firstName, String lastName) {
this.test1 = test1;
this.test2 = test2;
this.test3 = test3;
this.average = 0;
this.firstName = firstName;
this.lastName = lastName;
}
你的个人课错了。它没有属性或方法。没有理由延长它,因为它不会给党带来任何好处 如果属性对公众可见,则不需要getter或setter,但这并不意味着这是一个好主意 试着像这样思考:
public class Person {
protected String firstName;
protected String lastName;
public Person(String f, String l) {
this.firstName = f;
this.lastName = l;
}
public String getFirstName() { return this.firstName; }
public String getLastName() { return this.lastName; }
}
public class Student extends Person {
public static final int MAX_GRADES = 3;
private int numGrades = 0;
private int maxGrades;
private int [] grades;
public Student(String f, String l) {
this(f, l, MAX_GRADES);
}
public Student(String f, String l, int maxGrades) {
super(f, l);
this.maxGrades = (maxGrades > 0) ? maxGrades : MAX_GRADES;
this.grades = new int[this.maxGrades];
}
public void addGrade(int grade) {
if (this.numGrades < this.maxGrades) {
this.grades[numGrades++] = grade;
}
}
public double getAverageGrade() {
double average = 0.0;
if (this.numGrades > 0) {
for (int i = 0; i < this.numGrades; ++i) {
average += grade[i];
}
average /= this.numGrades;
}
return average;
}
}
公共类人物{
受保护的字符串名;
受保护的字符串lastName;
公众人物(字符串f、字符串l){
this.firstName=f;
this.lastName=l;
}
公共字符串getFirstName(){返回this.firstName;}
公共字符串getLastName(){返回this.lastName;}
}
酒吧
public Student(int test1, int test2, int test3, String firstName, String lastName)
{
this.test1 = test1;
this.test2 = test2;
this.test3 = test3;
...
}
this.average = 0; // Or maybe 'this.average = computeAverage();'
this.firstName = firstName;
this.lastName = lastName;